The present invention relates to a book document handling device for a copier, facsimile apparatus or similar image forming apparatus, and capable of reading a book document and turning over the pages of the document.
A book document handling device capable of reading the spread pages of a book document and then automatically turning over the page has recently been proposed in various forms. The problem with this kind of device is that when the right and left pages of a book laid on a table in a spread position are different in level, a scanning unit scanning the document rises or falls due to a step formed between the spread pages. The scanning unit, therefore, fails to read the book or to turn the pages stably. Hence, it is preferable that the right and left pages of the book be maintained flush with each other at all times.
To hold the spread pages of a book flush with each other, Japanese Patent Laid-Open Publication No. 61-184527 teaches a see-saw type document supporting device. This device urges the spread pages of a book against a single flat glass sheet overlying the document. However, although the glass sheet allows the scanning unit to read the spread pages stably, it prevents the scanning unit from turning the pages because it intervenes between the scanning unit and the book. As a result, the automatic page turning function particular to this kind of device is not available. In addition, a stable pressure is not achievable with the see-saw type device because the book is pressed against the glass sheet by the manual operation of a handle.
Japanese Utility Model Publication No. 60-12114 discloses a platen device for a copying a book. The platen device has a base and a pair of independent document tables mounted on the base. The tables are each movable up and down and constantly biased upward by a resilient member. A platen covers the upper surfaces of the tables and is selectively openable. The spread pages of a book are read through the platen. This kind of approach also has a problem that when the platen is present over the spread book, it is extremely difficult to turn the page of the book. If the platen is removed, it is likely that the book document is caught or torn off when the base or tables are inserted into the body of the device. Further, because the device constantly biases the book upward, the operator must set it while pressing the spread pages downward. Moreover, because the book is simply laid on the tables, it will be displaced if the platen is absent, resulting in skewed images. Therefore, the platen is essential with this device and cannot be removed. This kind of device is not applicable to a device for reading a book while turning the pages thereof.
Other book document handling devices are taught in the following documents:
Japanese Patent Laid-Open Publication No. 4-38867; PA1 Japanese Patent Laid-Open Publication No. 6-250296 PA1 Japanese Patent Laid-Open Publication No. 62-99737 PA1 Japanese Patent Laid-Open Publication No. 54-21836 PA1 Japanese Patent Laid-Open Publication No. 61-284492 PA1 Japanese Patent laid-Open Publication No. 56-60294 PA1 Japanese Patent Laid-Open Publication No. 60-122932 PA1 Japanese Patent Laid-Open Publication No. 63-47197 PA1 Japanese Patent Laid-Open Publication No. 62-35891 PA1 Japanese Patent Laid-Open Publication No. 62-267196 PA1 Japanese Patent Laid-Open Publication No. 57-208300 PA1 U.S. Pat. Nos. 4,693,594 5,325,213 PA1 4,017,173 4,218,130 PA1 4,659,207 4,673,286 PA1 4,688,930 4,916,839 PA1 4,942,482 4,972,271 PA1 5,077,577 5,084,732 PA1 4,982,235 4,856,769 PA1 4,985,617 5,119,136 PA1 4,823,395 3,594,079 PA1 4,645,331
However, the devices taught in the above documents also have the problems discussed or bring about other problems although not described specifically.